Cyclone design procedure

All cyclone design procedures bear the inherent condition that the solids enter uniformly dispersed over the cyclone s inlet area. This is generally the case where a cyclone is hung inside a vessel above a... 

Cyclones have been used to remove particulates from gas streams since the middle of the 19th century (Rietema and Verver, 1961). Early researchers (Rosin et al., 1932 Alexander, 1949 Stairmand, 1951 Ter Linden, 1949 linoya, 1953 Lapple, 1951 van Tongren, 1936) conducted the first experiments designed to understand the operation of this mechanically simple but operationally complex device. Many of these experiments (Ter Linden, 1949 Lapple, 1951 Stairmand, 1951, etc.) resulted in cyclone designs based on relative cyclone dimensions. More recently, Zenz (1975) developed an empirical cyclone design procedure that has achieved popular acceptance in the United States. 

One equation that has been used extensively in cyclone design procedures is that of Lapple (1940). This equation replaces the smallest theoretically collected particle size with a particle size, Dp th, collected by the cyclone with a theoretical efficiency of 50%, thus... 

The cyclone design procedure developed by Zenz (1975) utilizes Eq. (4) as the basis of the design procedure. The procedure consists of several steps ... 

The cyclone design procedure that has just been described is a tool that can be used to estimate cyclone efficiency. As with most calculation procedures, there is always a diflference between what is measured and what is calculated. As Zenz (2001) notes, the primary difference between the measured efficiency and the calculated efficiency using this method is due to the correct estimation of the actual particle size entering the cyclone. Agglomeration can occur in fine dusts to such an extent that the actual cyclone efficiency can be much greater than calculated. 

The following design procedures can be used to size a cyclone with a specified fluid flow rate and physical property data ... 

The conventional hydrocyclone design procedures have been based on a rather simplistic view of the hydrocyclone function the cyclone size is selected from the capacity and available pressure drop requirements, with the cut size not being a free choice but fixed by the former two requirements (reduction in cut size can only be achieved by using a greater number of smaller cyclones in parallel). This approach ignores completely the effect of the underflow orifice size on the cut size, and also on the solids concentration in the imderflow. The procedure based on the model in section 6.6.6 centres... 

The sizing procedure is presented in Guidelines for Pressure Relief and Effluent Handling Systems (AIChE-CCPS, 1998). Figure 23-53 shows the dimensions of a cyclone separator designed in accordance with this procedure. If liquid is continuously drained from the cyclone to a separate accumulator, a vortex breaker and false bottom should be used (Fig. 23-53, view BB). 

In these systems, the total collection efficiencies of the dry product are 85 per cent for the drying vessel, 90 per cent for the cyclone collector and 98 per cent for the scrubber-condenser. The net efficiency of the system may be as high as 99.97 per cent if the scrubber effluent is considered as product. All the runs are based on 1.25 kg/s product and 0.75 kg/s evaporation at an elevation of 300 m above sea level. The total air flow is measured at the outlet before the stream is split into the recycle and bleed portions and, for such flows, the design of suitable fans is outlined by Jorgensen164 . The calculations outlined here may be confirmed by the use of psychometric charts, and this procedure has been considered in some detail by Cook and Demount165. ... 

It should be pointed out here that the scale-up procedure described here is specifically designed for separation or classification of fine particles. These are the particles predominantly used in the chemical industry and the approach, using dimensionless groups, is in common with the treatment of other unit operations in chemical engineering. The geometrical similarity concerns all internal dimensions of the individual cyclones except the size of the underflow orifice which is regarded here as an operational variable. 

Schulenberg and Starflinger (2012) reported about a constant pressure start-up and shut-down system for the three-pass core design of the HPLWR, trying to keep the feed-water temperature constant to minimize thermal stresses of the reactor pressure vessel. This concept also includes a warm-up procedure for the deaerator during startup from cold conditions. A battery of cyclone separators is foreseen outside of the containment to produce some steam from depressurized hot coolant of the reactor. 

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